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BRAMPTON, ON, CANADA | BE has shipped what it says is the world's first 11-layer blown film line from its plant in Brampton to an undisclosed customer. The 11-layer SCD die is an industry first, and so is the solution that BE developed to accommodate the 11 extruders around the die.

As the number of layers goes up, the extruder arrangement becomes increasingly constricted. BE's engineering group knew that arranging 11 extruders radially around the SCD die would require longer adaptors and result in a very crowded hot section. A suitable extruder arrangement needs to accommodate a die access platform and leave enough room between the extruders for servicing access. Ideally, for barrier film coextrusion the adaptors should be short and straight.

BE's innovative solution was to design piggybacked extruders, or two extruders with one mounted on top of another. The design of the SCD provides a good marriage for piggybacked extruders since the extruder center line heights are different for each layer. The configuration for the 11-layer line then became two piggybacked extruders plus seven normal extruders, creating a radial extruder configuration similar to a 9-layer line but with two of the extruders being doubles.